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Numbers are in: 37,000 Australians can avoid a cancer diagnosis each year

Numbers are in: 37,000 Australians can avoid a cancer diagnosis each year

Food for thought in first ever Australian study counting cases by cause

Around 37,000 Australian cancer cases could be prevented each year largely through lifestyle change, according to the first ever study* of cancer incidence and preventable causes in Australia.

The study, funded by Cancer Council Australia and conducted by QIMR Berghofer Medical Research Institute, showed that one in three cancers in Australia could be prevented.

Cancer Council Australia CEO, Professor Sanchia Aranda, said the ground-breaking research should encourage Australians to be positive about reducing their risk.

"Of 13 identified risk factors, smoking, UV radiation, body weight, poor diet and alcohol caused around 90 per cent of all preventable cancers,” Professor Aranda said. "It's time to bust the myth that everything gives you cancer and do more to reduce the risks that we know cause cancer.

"The association with smoking is well-known, but the study shows that 7000 new cancer cases a year are also attributable to low fruit and vegetable intake, low fibre intake and eating excess red meat. Eating more fruit, vegetables and wholegrains is a positive step we can take to reduce our risk. These healthier choices also reduce obesity, the cause of 3900 cancer cases in its own right, and balance overconsumption of red and processed meat, which account for a further 2600 cases.

"People are confused about fad diets and mixed health messages, but the evidence is clear that a diet rich in vegetables, fruit and whole grains, with other foods consumed in moderation, will cut your cancer risk. Now we can back that advice with data on cancer case numbers, to emphasise why we urge people to adopt a cancer-smart lifestyle."

Professor Aranda said the study estimated incidence attributable to risk factors as specific as the 3200 cancer cases caused by alcohol and the 1550 cases caused by low fruit consumption alone.

Professor David Whiteman from QIMR Berghofer, who led the study, said the risk factors considered in the report had to meet three conditions – be classified by the World Health Organisation or the World Cancer Research Fund as a cause of at least one cancer type; be modifiable; and there had to be reliable data on numbers of Australians exposed to the risk factor. He said there was sufficient evidence to associate 13 different factors with 24 cancer types, including some cancers with high mortality.

"In addition to lifestyle risk factors, we analysed the impact of hepatitis B and C, human papillomavirus, HIV and Epstein Barr virus,” Professor Whiteman said. "Hopefully the study will help guide lifestyle change and health policy in Australia, and contribute to the international evidence on cancer prevention."

Professor Aranda said the findings showed the importance of research and evidence to inform public policy and individual choice. “This is the most comprehensive study of its kind ever published in Australia and it provides clear guidance on cutting your cancer risk. It should help motivate all Australians to take simple steps towards a healthier lifestyle."

Cancers in Australia in 2010 attributable to modifiable factors was commissioned by Cancer Council Australia and conducted by QIMR Berghofer Medical Research Institute. It has been published in the Australian and New Zealand Journal of Public Health. The research seeks to determine the proportion of cancer cases in Australia that are caused by a modifiable known cancer risk factor or exposure (e.g. smoking tobacco, drinking alcohol, eating too much red meat etc.) The researchers also estimated how many cancer cases could be prevented if reasonable measures were taken. The methodology and key findings are summarised follow.

Methodology

Researchers estimated the population attributable fraction (PAF)* of cancers associated with exposure to 13 established causal factors using standard formulae incorporating exposure prevalence (how much people consume or are exposed to) and relative risk data (the extent to which that factor is linked to or causes certain cancers). They also calculated the potential impact of changing exposure to some factors.

*The PAF estimates the proportion of cancers in the population that can be attributed to a specific risk factor. e.g. an estimated 81% of all lung cancers can be attributed to the fact that people smoke.

Key findings

A total of 32% of all cancers diagnosed in Australia (excluding non-melanoma cancers) were attributed to the 13 cancer risk factors assessed.

This translates to up to 37,000 cancers (or one third of all cancers) being preventable each year in Australia**

33% of cancers in men and 31% in women are estimated to be preventable.

**this is fewer than the total for each risk factor below because some cancers may be attributed to more than one risk factor, e.g. All (100%) cervical cancers are attributable to HPV infection but some can also be attributed to the fact that women smoked and/or used the oral contraceptive pill.